Evaporative Chiller Using Plate Type String-Screen-Fills as Heat Exchanger and Fabrication Thereof

ABSTRACT

The present invention involves an evaporative chiller using a plate type string-screen-fill heat exchanger which is formed of a multiplicity of plate type string-screen-fills with string screens on their both sides. The hot water sprayed on the top perforated plate of the heat exchanger is imbibed into holes on the top plate by surface tension of strings suspending over the holes and then flows down on the surface of strings. During its flowing down on the surface of strings, the water is cooled through evaporation and convection mechanisms of water by contacting with air traveling transversely or slantly through the strings by means of a forced draft. The construction cost and electric consumption saving of the present invention are less than half cost of the current chiller and more than 30%, respectively. The fabrication method of the plate string-screen-fill heat exchanger is described in the present invention.

CROSS-REFERENCE TO RELATED APPLICATION REFERENCES CITED U.S. Patent Documents

-   U.S. application Ser. No. 13/053,382, Mar. 22, 2011. Park -   U.S. Application No. 61/726,928, Ser. No. 11/21/2012. Park -   U.S. Application No. 61/736,646, Ser. No. 12/13/2012. Park -   U.S. application Ser. No. 13/888,327, Jun. 6, 2013. Park

Foreign Patent Documents

-   KR 100393126 Jul. 18, 2003 Park -   KR 100516391 Sep. 14, 2005 Park -   KR 100516392 Sep. 14, 2005 Park -   PCT WO 2005/008159 A1 Jan. 27, 2005 Park

OTHER PUBLICATIONS

-   Telstar International Technology Co., Ltd.,     http://www.telstar-tech.com.tw/Product/fan-04.htm -   Cooling Tower Depot, Cross Flow Fill With Louver or Drift     Eliminator, -   http://www.streamlineextrusion.com/files/manuals/paper4.pdf. -   STAR COOLING TOWERS, Counterflow and Crossflow Film Fills, -   http://starcoolingtowers.com/coolingtowerfill -   Wikipedia, http://en.wikipedia.org/wiki/Wind_chill

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING CPMPACT DISC APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to chiller utilizing evaporative cooling fill medium heat exchanger. More precisely, the present invention relates to an evaporative chiller using plate type string screen fills as a heat exchanger, which is fabricated with strings, using the unique characteristics of string: flowing down of water on the surface of the vertical string by gravity force, surface tension of string strong enough to hold the water on the surface of string against the strength of cooling air draughts, and capability of contacting water and cooling air with barely resisting air flowing through the strings.

2. Description of the Related Art

Cooling of warm water by contacting with ambient air is accomplished mainly through evaporation of water molecules and convection of heat. The evaporation of water molecules needs latent heat plus specific heat of water. Absorbing the evaporation heat from the warm water, the water molecules are vaporized to become vapor and in turn the warm water loses its preserved heat by that much heat transferred to the air. If air is not moving around the surface of warm water, the vapor molecules accumulates to saturate and then the effective evaporation is terminated. The convection of heat is to transfer heat from warm water to cooler air, which means the warm water dissipates its heat to the cooler air around the surface of warm water. Then, the warm water loses its heat and reversely the cooler air around the surface of warm water gets warmer. The warm air forms an insulating boundary layer around the surface of warm water. The warm air insulation layer resists a transfer of heat from warm water to air to terminate the transfer of heat from warm water to air. If air is moving around the surface of warm water, the moving air disrupts both of the saturated vapor and the boundary layer of the warm air, allowing for new dry and cooler air to replace the humid and warm air around the surface of warm water to continuously cool the warm water. Therefore, the rate of heat loss on the surface of warm water through evaporation and convection depends on the blowing speed of air on the surface of warm water. Such an effect of cooling speed is a wind chill whose effect is to quickly reduce the warm water cooler than the ambient temperature, but it cannot reduce ultimately the temperature of warm water below the ambient temperature. See reference of http://en.wikipedia.org/wiki/Wind_chill for more information on cooling effects of moving air. To use such cooling mechanism of warm water by contacting cool air and warm water, PVC film fills are adapted in current cooling towers.

Currently, a chiller or cooling tower is employed to cool warm water to prevent industrial hot temperature equipment, like metal melting crucible, extruder, hot sintering furnace, etc., as well as a building air conditioning system, from breaking down by heat overload. The chiller consists of compressor, heat exchanger (condenser), water tank cooing hot water, water circulation pump for cooling heat generator, and cooling tower or air cooling fan. The chiller cools hot water by contacting with low temperature refrigerant flowing in coolant pipes which locate in the water tank. The low temperature refrigerant is provided by the operation of compressor. The operation of compressor requires a large amount of electricity. Therefore, the larger the chiller is, the more consumption of electricity cannot be avoided. Such a mode of operation of chiller is one of disadvantages of the current chiller. Another disadvantage is that the operational loop of the compressor includes compressor, condenser, cooling tower or cooling fan, expansion valve, and cooling chemical agent. Such fabrication requiring several components increases fabrication cost of the current chiller. And the further disadvantage is that the current chiller is not environmentally friendly due to a usage of the cooling chemical agent which is one of environmental pollutants. The cooling towers are categorized into open and closed loop cooling tower. The closed loop cooling tower cools the heat generator by passing the cooled water through the surface of heat generator or by indirectly cooling a buffer water tank cooling the heat generator by passing the cooled water through the water circulation loop pipe in the buffer water tank. Such operation of the closed cooling tower cannot avoid an insufficient cooling effect due to indirect contact of cooled and warm water, which limits application of the closed loop cooling tower. The open loop cooling tower cannot be applied to the cooling of the heat generator due to accumulation of particles in the cooling surface area of the heat generator and in the cooling water loop because of particles contaminated into the water through cooling tower from environmental atmosphere. Another minor disadvantage of the open and closed loop cooling tower is the ice spike of water pipe in winter. To prevent the ice spike of the water pipe, a careful maintenance of the cooling tower is necessary and for the operation of heat generator in winter, other cooling system should be used.

To compensate such disadvantages of the current chiller and cooling tower, the evaporative chiller was recently invented and patented by the inventor of the present invention, such as described in Korean Patent 100393126, 100516391, 100516392, and PCT/KR3004/001825. The evaporative chiller is schematically drawn in FIG. 1. The FIG. 1 shows that the evaporative chiller consists of string heat exchanger, vapor condenser, fan blower, and water circulation pump. The string heat exchanger and vapor condenser are invented by the present inventor to eliminate the disadvantages the PVC film fills pack of the current cooling towers (U.S. application Ser. No. 13/053,382). The string heat exchanger is applied to the evaporative chiller of the present invention. The string heat exchanger was fabricated with polyester strings and comprises one or more large string fills packs in shape of large rectangular column of 50(W)×25(D)×100(H) cm fabricated with more than several hundreds of strings. Hence, one rectangular large string fills pack required a long fabrication time due to threading a long string through the holes on the top and bottom plates separated by 100 cm in the column. The fabrication method is described in Korean Patent No. 100393126. Such a manufacturing feature was a significant disadvantage of the patented string evaporative chiller to be brought to marketing. Therefore, it was necessary to have invented a new fabrication technology of a large string fills pack able to tremendously reduce its manufacturing time. To achieve this aim, an innovative Plate Type String-Screen-Fill (SSF) was invented to be easily assembled into a large string fill pack, which is in a rectangular frame whose thickness is in the range of 1 to 4 cm with vertical-string-screens (VSS) on both sides of the SSF. The fabrication of SSF was applied to U.S. patent and is on pending at present time. The fabrication method of SSF is described in detail in the U.S. patent application (U.S. patent application Ser. No. 13/053,382).

The water cooling functions and advantages of the rectangular string fills pack previously invented by the present inventor are briefly described in this section. When the water to be cooled is sprayed on the top perforated plate of the rectangular string fills pack, the sprayed water spreads over the top perforated plate and is imbibed down through the holes by the surface tension of strings suspending from and through the holes on the top and bottom plates of the string fills pack, then flowing down on the surface of strings. The water flowing down on the surface of strings becomes circumferential thin film water on the circular surface of string, which can make a contacting area between water and cooling air maximized and also make the water as thin as possible. Such conditions of the water flowing down on the surface of strings are significant advantages of strings to provide high water cooling efficiency of water. And another significant advantage of string is that the flowing down of water on the surface of strings do not create any conditions of forming scales and fouling on strings, which means no formation of the scales and fouling in string fills pack, resulting in no-reduction of the flowing rate of cooling air and the serve life of string fills pack.

The purpose of the present invention is a fabrication of the evaporative chiller using the innovative plate type string-screen-fills being free of the disadvantages exhibited in the large string fill media evaporative chillers, requiring a much less fabrication efforts and far lower fabrication cost.

SUMMARY OF THE INVENTION

To eliminate the disadvantages of chiller currently in use and large string evaporative heat exchanger described above and to improve the fabrication of the evaporative chiller, the Plate Type String-Screen-Fills (SSFs) invented by the present inventor, applying to U.S. patent (U.S. application Ser. No. 13/053,382), are applied and proved to be adequate for their application to the evaporative chiller, since they have several advantages given as follows.

-   1. They can be simply fabricated without great efforts. -   2. They have a high water cooling efficiency. -   3. They are not attacked by any water chemicals because they are     made of inert materials like polyester, high density polyethylene,     and aluminum (any other materials are possible). -   4. They deploy a large surface area in a relatively small volume,     thereby maximizing heat transfer. -   5. They can operate at high water temperature in excess of 57° C.     (135° F.) without loss of their physical integrity or mechanical     strength. -   6. Their materials are non-toxic, non-hazardous, and suitable for     easy and safe disposal at the end of service life.

The fabrication of the evaporative chiller is completed through four steps of fabrications: determination of fabrication factors, the fabrication of SSFs and SSF packs, installation of the SSF packs into the evaporative chiller, and performance test of the evaporative chiller. The determination of fabrication factors of SSF and SSF pack requires determination of a lot of factors such as string materials and type, hole size on the top and bottom perforated plate of the evaporative heat exchanger, interval between adjacent strings in the heat exchanger, specific number of strings per unit cross section area of SSF pack, variation of specific area of SSF pack depending on string diameter, water cooling effective length of string in the heat exchanger, verification of flying away of water from strings, slanting angle of string slantly installed in the heat exchanger, correlation factor for computation of hole size from arbitrary string size, and cooling effect due to string type. The fabrication of SSFs and SSFs packs includes fabrication of SSF frame including attachment tabs and semi-circular holes on frame, winding string over the SSF frame, and assembly of plurality of SSFs into SSF pack. One or more SSF packs are installed into the location of the heat exchanger in the evaporative chiller and then finally the performance of the evaporative chiller is tested. The determination of fabrication factors of the SSF and SSF pack and the fabrication of SSF and SSF pack are described in detail in the previous invention of String-Thick-Plates (STP) Pack for Use in Cooling Tower (U.S. application Ser. No. 13/053,382) invented by the present inventor. The installation of SSF packs in the evaporative chiller and its performance test are described here in the present invention and also the fabrication of the SSF and SSF pack is briefly described.

<Evaporative Chiller of Present Invention> The SSF evaporative chiller of the present invention provides two distinct vital functions: (1) cooling of hot water, flowing down on the surface of strings suspending from the top and bottom perforated plate of SSF heat exchanger, by evaporation and convection mechanism of water contacting with air transversely traveling through the strings after entering the SSF heat exchanger passing the air filter on the air entrance of evaporative chiller and (2) eliminating of vapor, generated through cooling process of hot water in the SSF heat exchanger, by condensing and absorbing vapor on the cold water flowing down on the surfaces of strings vertically and slantly suspending from the top and bottom of the vapor absorber in the cross current evaporative chiller (CrCEC) and counter current evaporative chiller (CoCEC), respectively. Such evaporative chillers are fabricated as in the same configurations as the SSF media cooling towers are fabricated, so that they are categorized as cross current and counter current evaporative chillers.

The CrCEC of the present invention are fabricated in several configurations to meet required demands of fabrication. Their configurations are determined due to the arrangement of SSF pack heat exchanger in the CrCEC and their key components are SSF pack heat exchanger, vapor absorber, water circulation pump, and vacuum exhaust fan blower. A basic standard CrCEC of the present invention is schematically illustrated as shown in FIG. 1, which contains one single heat exchanger fabricated with SSF packs shown in FIG. 2. FIG. 1 shows a horizontal straight-lining-up of the SSF pack heat exchanger, vapor absorber, and vacuum exhaust fan blower in their sequential order and the water circulation pump positioned on the floor of chiller. The SSF pack heat exchanger is a heat exchanger for cooling hot water and the vapor absorber removes vapor generated due to cooling hot water in the SSF pack heat exchanger. The vacuum exhaust fan blower blows an environmental air into the evaporative chiller through its air entrance and then pull the air to travel through the SSF heat exchanger and vapor absorber to be exhausted out of the chiller into environment through the vacuum exhaust fan blower. The water circulation pump pumps out water from a cold water reservoir at the bottom of the SSF pack heat exchanger to be circulated through a heat generator, which is operated in industrial facilities, to be cooled and then sprayed onto the top of SSF pack heat exchanger. Such a circulation of water is accomplished through a water circulation loop of pipe. The vapor absorber has a capability of removing a part of vapor by condensing vapor on the surface of cold water flowing down on the surface of strings imbedded in the vapor absorber and discharging the rest of vapor out of the chiller through the vacuum exhaust fan blower. Other type CrCECs of the present invention consist of two or more SSF pack heat exchangers which are configured in a symmetrical position around the vacuum exhaust fan blower such as rectangular, square, and regular hexagonal SSF evaporative chillers and in a non-symmetrical position like a regular pentagonal SSF evaporative chiller as shown in FIGS. 3A, 3B, 3C, and 3D, respectively.

Basic standard CoCEC of the present invention are schematically illustrated as shown in FIGS. 4A and 4B, which contain a single story of V-type and X-type SSF pack heat exchanger, respectively. The key components of the CoCEC are vertically lined up as shown in FIGS. 4A and 4B. Namely, the V-type or X-type SSF heat exchanger is positioned at the bottom of the chiller and the vacuum fan blower at the top of chiller, and the vapor absorber is located between them. The water circulation pump is on the floor of chiller. When the CoCEC is operated, air is flowing up along the vertical length of the chiller and water is flowing down on the surfaces of the slanted strings and therefore the air and water are passing each other in the opposite direction to form a slant angle of 30 degree, since the strings of the slanted SSF fills are slanted by 30 degree. Such a flowing pattern of water and air in the CoCEC is “semi-counter current”. The V-type SSF evaporative chiller consists of one story of V-type SSF heat exchangers, while the X-type chiller has a capability to pile the X-type SSF heat exchangers on the top of previous X-type heat exchangers to build a long high chiller tower. Hence, the X-type CoCEC has advantage to cool hot water which needs a long contacting time of air and water to reach a required temperature and also it has advantage to absorb fume gas when applied to remove ammonia gas from livestock houses.

The SSF evaporative chiller is installed inside or outside building. The SSF evaporative chiller to be installed inside building requires a vapor exhaust duct connected outside building from the chiller and sirocco fan blower which strongly sucks and discharges air (see reference of Telstar International Technology Co., Ltd.), while the vapor exhaust duct is not necessary and the ventilation fan blower is preferred when the SSF evaporative chiller is installed outside building. When the SSF evaporative chiller is installed outside building, the ventilation fan blower is attached on the top or side wall of the chiller with automatic louver damper at the outside of fan to prevent coming-into of dusts. To blow out the vapor through the vapor exhaust duct, the sirocco fan blower is indispensable, because it has a strong suction and discharging of air through the duct. Hence, the sirocco fan blower is attached on the top or side wall of the chiller inside building as shown in FIGS. 5A and 6A, respectively and to eliminate an operating noise of fan, it is installed outside building by attaching at the end of duct as shown in FIG. 6A.

<Fabrication of SSF and SSF Pack> Fabrication of the SSF and SSF pack invented by the present inventor is briefly described as follows. The SSF pack is schematically shown in FIG. 2, which is a standard SSF pack in a rectangular column to be installed in a string evaporative heat exchanger of the evaporative chiller of the present invention. The standard SSF packs are in dimensions of 25(W)×25(D)×75(H) and 50(W)×25(D)×100(H) cm (other dimensions are possible) which are used as basic SSF pack for designing and fabrication of string evaporative heat exchangers for fabrication of the evaporative chiller. FIG. 2 shows that inside the SSF pack are many strings tightly suspended from through the holes on the top and bottom perforated plates of SSF pack and the sides of SSF pack are paneled with side frames of SSF, and the front and rear sides of SSF pack are open for cooling air to enter the SSF pack and pass through it under a guiding control of side panels as shown in FIG. 2. When the SSF pack is in serve, the water pumped on the top of SSF pack is imbibed into the string loaded through holes on the top perforated plate by surface tension of wet strings suspended from through the holes and then flow down on the surface of strings. While the water is flowing down on strings, the water contacts with cooling air transversely traveling through the strings to be cooled.

The SSF pack is fabricated by assembling a plurality of SSFs invented by the inventor of the present invention. One unit of SSF is a rectangular shaped string screen plate with two vertical-string-screens (VSSs) on its both sides, which are apart in 1 cm, other dimensions are possible, and strings are wound over the top and bottom frames in the longitudinal direction as shown in FIGS. 6A and 6B. The VSS is comprised of several strings vertically suspended from the top and bottom frames separated sufficiently apart from each other as shown in FIGS. 6A and 6B. FIG. 6A shows the SSF to be used in a cross current SSF heat exchanger, referring to cross current SSF (CrC-SSF), and FIG. 6B in counter current SSF heat exchanger, referring to counter current SSF (CoC-SSF). The CrC-SSFs and CoC-SSFs are assembled in SSF packs which are installed in the string heat exchanger as shown in FIG. 2 and FIGS. 4C and 4D, respectively. Therefore, one single SSF pack is a basic standard SSF pack, 25(W)×25(D)×75(H) and 50(W)×25(D)×100(H) cm, necessary to fabricate a large SSF pack to be used for the large evaporative heat exchanger.

The SSFs are fabricated by winding a single long string over the top and bottom frames of rectangular frames of the SSFs and then as shown in FIGS. 7A and 7B, the CrC-SSF and CoC-SSF are fabricated, respectively. In case of using string of 5 mm in diameter, the small and large standard frames have respectively 32 and 64 semicircular holes of 9.6 mm in diameter on each of their both sides. Their intervals between the centers of the adjacent semi-circular holes are 19.6 mm, other intervals are possible. The CrC-SSF and CoC-SSF are fabricated by tightly winding a long single string of 5 mm in diameter by 16 or 32 turns passing through the semicircular holes separated by 39.2 mm, on the sides of the top and bottom frames shown in FIGS. 7A and 7B. Hence, the string loaded CrC-SSF and CoC-SSF are fabricated as shown in FIGS. 7A and 7B, which consist of one half (16 or 32 strings loaded semi-circular holes) of total number of strings on the VSS on each side and whose thicknesses are 17 mm. When 18 units of CrC-SSFs or CoC-SSFs are assembled together, a standard CrC-SSFs pack or CoC-SSFs pack in dimension of 25(W)×25(D)×75(H) cm are produced with a completed VSS including 32 strings on both sides of SSF.

<Fabrication of Vapor Absorber> Using a condensing of water vapor on cold materials (lower temperature than a dew point of water vapor), the vapor absorber is fabricated to condense the water vapor on cold water flowing down on the surface of strings. The fabrication method of the vapor absorber is exactly same with that of the SSF pack heat exchanger. However, the vapor absorber is small and the spacing of strings loaded in the vapor absorber is much shorter than in the heat exchanger and therefore the specific surface area of the strings of 2.5 mm in diameter is increased by 4 times, which is 60 ft²/ft³ compared with 15 ft²/ft³ of the SSF pack heat exchanger. The cold water is supplied from tap water whose temperature is in the range of 50 to 68° F. in Summer and 40 to 55° F. in Spring and Fall. Hence, since the temperature and humidity of the vapor in the SSF evaporative chiller is around 75 to 85° F. and higher than 85%, respectively, the dew point of the 85% vapor is in the range of 70 to 79° F. Then, the tap water temperature, 50 to 68° F., is lower than the dew point of the vapor generated in the SSF evaporative chiller. Therefore, most vapor generated by the SSF evaporative chiller in all seasons is removed from the exhaust air stream by the vapor absorber. As a result of removal of vapor from the exhaust air stream, a white smoke exhausted from the duct of SSF evaporative chiller produced due to exhausting of vapor is not shown up. The vapor absorber is designed for the tap water to be supplied to the top of vapor absorber by the rate of a half gallon per min per square feet (other rate is possible) of the top surface of vapor absorber and to be added to main stream of circulation water after passing through the vapor absorber. The vapor absorber is fabricated in a rectangular shape for CrCEC as shown in FIG. 1 and in a V letter shape for both of V-type and X-type CoCEC as shown in FIGS. 4A and 4B.

<Advantages of Present Invention> One of major advantages of the present invention is the ability to substantially reduce the electric consumption of current chiller by more than 30% because the present invention does not use compressor. The larger cooling capacity of the evaporative chiller, the smaller amount of electric consumption can be expected.

Another major advantage of the present invention is the ability to fabricate the evaporative chiller in several shapes other than rectangular like square, pentagon, and hexagon, whose wall surfaces are used as the entrance of cooling air, providing high cooling efficiencies.

Yet another major advantage of the present invention is the ability to fabricate the evaporative chillers with any of the square, pentagon, and hexagonal cross current evaporative heat exchanger, but hexagon is preferred to other shapes, to provide the best operating conditions such as usage of smaller space due to smaller size and less restriction of construction place.

Another major advantage of the present invention is the ability to easily fabricatd and install the SSF packs without spending great efforts by press joining attachment and piling tabs on the frames of SSFs and easy carrying the SSF packs because of their light weights.

Minor advantage of the present invention is the ability to eliminate the production of a white smoke which is usually exhausted from cooling towers.

Minor advantage of the present invention is the ability to be in service life of more than 25 years since the polyester strings and aluminum used in the present invention has excellent physical and chemical properties like high melting temperature, high resistance to most chemicals, high tenacity for stretching and shrinking, and high durability.

And further advantage of the SSF packs of the present invention within the cooling towers is that the materials of the SSF pack, polyester strings, aluminum or aluminum alloy, polypropylene, are non-hazardous and suitable for safe and disposal at the end of service life.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic picture of SSF evaporative chiller.

FIG. 2 is a schematic picture of standard plate type string screen fills (SSFs) pack assembled SSFs to be installed in cross current evaporative chiller.

FIG. 3A shows a schematic picture of a rectangular cross current evaporative chiller.

FIG. 3B shows a schematic picture of a square cross current evaporative chiller.

FIG. 3C illustrates a regular pentagon cross current evaporative chiller.

FIG. 3D illustrates a regular hexagon cross current evaporative chiller.

FIG. 4A illustrates a schematic picture of typical counter current (semi-counter current) evaporative chiller with V-type assembled CoC-SSF packs and traveling direction of cooling air.

FIG. 4B illustrates a schematic picture of typical counter current (semi-counter current) evaporative chiller with cross type assembled CoC-SSFs packs and traveling direction of cooling air.

FIG. 4C illustrates the side view of V-type CoC-SSF packs installed in V-type counter current evaporative chiller.

FIG. 4D illustrates the side view of Slanted CoC-SSF packs installed in X-type counter current evaporative chiller.

FIG. 5A shows Image of picture of installation of sirocco fan blower in duct on the top of the SSF evaporative chiller.

FIG. 5B shows the side view of sirocco fan attachment on the top of the SSF evaporative chiller.

FIG. 6A shows Image of picture of installation of sirocco fan blower in duct on the side of the SSF evaporative chiller.

FIG. 6B shows the top view of sirocco fan attachment on the side of the SSF evaporative chiller.

FIG. 7A is a schematic picture of CrC-SSF.

FIG. 7B is a schematic picture of slanted CoC-SSF.

FIG. 8A is a schematic operation diagram of SSF evaporative chiller of the present invention.

FIG. 8B schematically illustrates an operation diagram of commercial wet chiller connecting primary, secondary, and tertiary loops. FIG. 8C shows a schematic picture of operation diagram of commercial dry chiller connecting primary and secondary loops.

<Description of Number in the Drawings> 1 standard SSF evaporative chiller, 2 rectangular CrC-SSF heat exchanger, 3 hot water sprayer, 4 top perforated plate of rectangular CrC-SSF heat exchanger, 5 bottom perforated plate of rectangular CrC-SSF heat exchanger, 6 air filter, 7 air stream and its flow direction, 8 cold water reservoir, 9 tap water solenoid valve, 10 tap water inlet port, 11 tap water supplying pipe to vapor absorber, 12 water inlet pipe to water circulation pump, 13 water circulation pump, 14 hot water inlet port, 15 cold water outlet port, 16 water flow meter/thermometer, 17 water flow meter/water filter/thermometer, 18 rectangular shape vapor absorber, 19 fan blower, 20 hot water inlet pipe to SSF heat exchanger, 21 SSF pack to be installed in cross current evaporative chiller or CrC-SSF pack, 22 SSF (simple notation of CrC-SSF, single unit of SSF), 23 string, 24 top perforated plate distributing water into the SSFs pack; 25 bottom perforated plate passing water out of the SSFs pack, 26 string loaded hole passing water through hole, 27 guiding wall to control direction of traveling of cooling air, 28 pathway of cooling air, 29 rectangular cross current evaporative chiller, 30 rectangular assembly of CrC-SSF packs, 31 square cross current evaporative chiller, 32 trapezoidal assembly of CrC-SSF packs, 33 pentagonal cross current evaporative chiller, 34 hexagonal cross current evaporative chiller, 35 V-type counter current evaporative chiller, 36 V-type SSF heat exchanger, fill media of CoC-SSF packs installed in V-type SSF heat exchanger in counter current evaporative chiller, 37 hot water distributer, 38 cooling air entrance of counter current evaporative chiller, 39 traveling direction of cooling air in counter current evaporative chiller, 40 V-type vapor absorber, 41 tap water supplying pipe to V-type vapor absorber, 42 tap water sprayer of vapor absorber, 43 vapor absorbed tap water returning pipe to cold water reservoir, 44 top perforated plate of V-type CoC-SSF pack, 45 X-type counter current evaporative chiller, 46 slanted rectangular CoC-SSF pack, 47 slanted CoC-SSF, 48 top perforated plate of slanted rectangular CoC-SSF pack, 49 V-type CoC-SSF pack, 50 side frame of slanted CoC-SSF, 51 bottom frame of slanted CoC-SSF, 52 top frame of slanted CoC-SSF, 53 sirocco fan blower, 54 image line of duct, 55 air traveling direction through sirocco fan blower, 56 SSF evaporative exchanger equipped with multi-SSF heat exchangers, 57 attachment line to SSF evaporative chiller; 58 top frame of CrC-SSF frame, 59 side frame of CrC-SSF frame, 60 bottom frame of CrC-SSF frame, 61 current commercial wet chiller, 62 primary coolant loop, 63 hot water pipe, 64 heat generator, 65 cold water pipe, 66 primary coolant water circulation pump, 67 water tank heat exchanger, 68 tap water supplying port, 69 water supplying controller, 70 secondary gas coolant loop, 71 cold coolant gas line, 72 gas expansion valve, 73 condenser, 74 hot coolant gas line, 75 compressor, 76 tertiary coolant water line, 77 warm water line, 78 cooling tower water circulation pump, 79 cooling tower, 80 dot line indicating primary coolant loop, 81 current commercial dry chiller, 82 air cooling fan, 83 air cooling condenser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

<Fabrication of Evaporative Chiller> The evaporative chiller 1 is fabricated by employing 10 components such as SSF heat exchanger 2, vapor absorber 18, 40, vacuum exhaust fan blower 19, water circulation pump 13, solenoid valve 8, air filter 6, water filters 17, water flowmeter 16, 17, water thermometer 16, 17, and water sprayer 3. Among them, the key components, SSF heat exchanger 2, vapor absorber 18, 40, and vacuum exhaust fan blower 19, are horizontally installed in the CrCEC 29, 31, 32, 34 and vertically installed in the CoCEC 36 in their sequence order, and the water circulation pumps 13 in both evaporative chillers are installed on the floor of chiller as shown in FIGS. 1, 4A, and 4B. The air filter 6 is attached on the air entrance of the SSF heat exchanger 2 to filter dust from the air stream 7 coming into chiller 1 in order to prevent the strings 23 to get jammed with dust: The water filters 17 are installed in line of water supplying pipes 10, 14 to the SSF heat exchanger and vapor absorber 18, 40 to absorb the particles in the water streams returning from the heat generation system and being supplied from tap water to prevent building up of scales in the circulation loop and in the SSF evaporative chiller 1. The water flowmeters and thermometers 16, 17 are installed in lines of water supplying to the SSF evaporative chiller 1 and to the heat generation system 64 for verifying the operation of the chiller in their allowable operational limits. The water sprayer 3 is located at the top of the SSF heat exchanger 1 and uniformly sprays the hot water returned from the heat generator 64 over the top perforated plate 4, 44, 48 of the SSF heat exchanger 2. Those ten components are installed in the CrCEC 1 as shown in FIG. 1 and also their installations in the CoCEC 35, 45 are accomplished in the same way. When the SSF evaporative chiller 1, 35, 45 is operated, a part of vapor is exhausted out of the chiller so that the vapor should be discharged into environment out of building through duct. To exhaust air through the long duct out of building, a sirocco fan blower 53 with strong suction and discharging of air is essential. A sirocco fan blower 53 has a strong capability to suck and discharge the air out through a long duct. The sirocco fan blower 53 is installed on the SSF evaporative chiller 1, 35, 45 in two ways: on the top and side of the SSF evaporative chiller as shown in FIGS. 5A and 6A, respectively. For the single SSF heat exchanger 1 and symmetrical rectangular CrCEC 29 the sirocco fan 53 is installed on it either way of top as shown in FIG. 5A or side installations as shown in FIG. 6A. However; for the other types of CrCEC 31, 33, 34, the top installation is allowed, because the SSF heat exchangers 2 are positioned along the surroundings of chiller. For the CoCEC 35, 45, only the top installation of sirocco fan is possible as shown in FIG. 5A.

<Installation of SSF Packs in Evaporative Chiller> Installation method of the SSF packs 21 of the present invention is exactly same as installed in the evaporative chiller with one unit large evaporative heat exchanger 2 (KR 100494126) invented by the present inventor for CrCEC 2, 29, 31, 33, and 34, but quite different for CoCEC 35, 45. FIGS. 4A and 4B show the configuration of installation of V-type and X-type CoC-SSF heat exchangers 36, 46 in the CoCECs. The V-type CoC-SSF heat exchanger 36 is fabricated by installing of the V-type CoC-SSF packs 49 shown in FIG. 4C side by side and the X-type CoC-SSF heat exchanger 46 is constructed by installing of the slanted CoC-SSF packs 46 shown in FIG. 4D in the form of X letter. The V-type CoC-SSF packs 49 shown in FIG. 4C is fabricated by assembling the slanted CoC-SSFs 47 shown in FIG. 7B in the form of V letter. The slanted CoC-SSF pack 46 shown in FIG. 4D is made by assembling the long slanted SSFs 47 in the form of a slanted rectangle shape. The V-type and X-type CoC-SSF heat exchangers 36, 46 respectively shown in FIGS. 4A and 4B are a single story of CoC-SSF heat exchanger, which are the ones of standard CoCECs 35, 45. The fabrication of a tower-like CoCEC requires a vertical piling of CoC-SSF packs. The V-type CoC-SSF heat exchangers 36 are not proper for piling because water passing the V-type CoC-SSF heat exchangers 36 is not flowing down on to the top plates of the next lower V-type heat exchangers 36, whereas the X-type heat exchangers 46 are suitable for piling them on the top plates of the previous X-type heat exchanger 46. Thus, the tower-like CoCEC is constructed by vertically piling the X-type heat exchangers 46 through their several stories with the bottom plate of the X-type heat exchanger 46 placed on the top plate of the lower X-type heat exchanger 46. Likewise, the installation of the CoC-SSF packs 46, 49 are limited are installed only in the square type and tower-like evaporative chillers.

However, the cross current (CrC)-SSF packs 30 are employed in any shape of CrCECs 29, 31, 33, 34. The typical shapes of CrCECs in which the CrC-SSF packs 21 can be installed are rectangle 29, square 31, regular pentagon 33, and regular hexagon 34 (other shapes are possible) as shown in FIGS. 3A, 3B, 3C, and 3D, respectively. Such shape CrCECs have one fan blower 19 at their centers and same SSF packs 30, 32 which are symmetrically located around the fan blower 19 except the regular pentagon shape CrCEC 33. The rectangular shape CrCEC 29 shown in FIG. 3A is popular, because the SSF packs 21 shown in FIG. 2 are well fitted and simply installed in the rectangular shape 30. On the contrary, the other shape CrCECs 31, 33, 34 have advantage able to be fabricated to fit in any shapes of the available spaces. The square 31, regular pentagon 33, and regular hexagon shape CrCECs 34 have the entrance of cooling air at the entire outside wall of the CrCEC. Therefore, those types of CrCECs have higher specific surface area of strings 23 for contacting of water and cooling air than that of the rectangular shape CrCECs 30 shown in FIG. 3A, which means higher cooling efficiencies, resulting in reduction of the volume of evaporative chillers. Hence, they provide an effective usage of the construction space, since they are relatively small and can be designed to fit the available space. Especially, the hexagonal shape CrCEC 34 shown in FIG. 3D provide the highest cooling efficiency (most effective usage of space), as its shape is close to a circular shape which has the largest area among the shapes with the same perimeter. When the CrC-SSFs are installed in the rectangular CrCECs 29, the only rectangular shaped CrC-SSF packs 21 as shown in FIGS. 2 and 7A, but in case of installing CrC-SSFs in other shape CrCECs 31, 33, 34, their heat exchanging zones are in the shape of trapezoid 32 as shown in FIGS. 3B, 3C, and 3D. Hence, to fill the trapezoidal heat exchanging zones with CrC-SSFs, a special installation method of CrC-SSFs is required. The installation of CrC-SSFs in the trapezoidal heat exchanging zones is described in detail in reference of U.S. patent application Ser. No. 13/053,382.

<Operation of SSF Evaporative Chiller> Operation of the SSF evaporative chiller is described using the basic standard CrCEC 1 shown in FIG. 1. When the SSF evaporative chiller is connected to industrial heat generating facility 64, the coolant water flowing through the water circulation loop of 8→13→65→64→63→3→2→8 shown in FIG. 8A runs from the cooled water reservoir 8 through the water circulation pump 13 and heat generator 64 in industrial facility to the hot water sprayer 3 on the top of the SSF heat exchanger 2. The cooling air 7 comes into the SSF evaporative chiller 1 through the air filter 6 at the air entrance of the chiller 1 and then exhausts out of the chiller 1 into environment through the fan blower 19 after passing through the SSF heat exchanger 2 and vapor absorber 18 in the sequence order of air filter 6, SSF heat exchanger 2, vapor absorber 18, and fan blower 19. The such a passing route of cooling air 7 is illustrated in FIG. 1. Before operating the SSF evaporative chiller 1, heat generator coolant water fills the water reservoir tank 8 at the bottom of SSF heat exchanger 2 and water circulation loop 13 between the chiller and heater generator by supplying tap water 10. Then, the operation of SSF evaporative chiller 1 starts with initiating of pumping circulation water through water circulation loop of pipe 65, 63 from the water reservoir tank 8 at the bottom of the SSF heat exchanger 2 through the heat generator 64 of an industrial heat generation facility to the top of the SSF heat exchanger 2 by operating of the water circulation pump 13. At the same time of initiating the start-up of water circulation pump 13, tap water is supplied to the vapor absorber 12 through the tap water inlet port 10 and flows down on the strings 23 vertically suspended in the vapor absorber 18. After passing the vapor absorber 18, the water absorbed vapor flows down into the water reservoir tank 8.

The hot water supplied to the top of the SSF heat exchanger 2 is sprayed on the top perforated plate 4 through the water sprayer 3. The hot water sprayed on the perforated plate 4, 24 imbibes into the holes 25 on the perforated plate 4, 24 by surface tension of strings 23 suspended over the holes 25 and then flows down on the surfaces of the strings 23 to flow into the water reservoir tank 8. During flowing down the strings 23, the hot water is cooled. The cooled water is collected in the water reservoir tank 8 and the collected cooled water is recirculated through the coolant loop 62 to cool the heat generator 64. Right after starting the operation of water circulation pump 8, the operating of fan blower 19 at the rear of SSF evaporative chiller 1 starts, and then the cooling air 7 is sucked in to enter the SSF evaporative chiller 1 from indoor environment through the air filter 6 at the air entrance of SSF heat exchanger 2. The cooling air travels transversely through the strings 23 vertically suspending from top and bottom perforated plates 4, 5 of the SSF heat exchanger 2 and cools the hot water flowing down on the surface of strings 23 by contacting the hot water on the surfaces of strings 23 and blowing vapor away from the strings 23 into cooling air stream 7. The high humid air passing through the SSF heat exchanger 2 continues to enter the vapor absorber 18 and travel perpendicularly to the streams of cold tap water flowing down on the strings 23 vertically suspended in the vapor absorber 18. During passing through the vapor absorber 18, the vapor in the air stream is condensed by contacting with the cold tap water and absorbed in the tap water stream, which flows into the water reservoir tank 8 and is added to the heat generator coolant water. Some amount of vapor remains in the air stream 7 and is discharged into the environment through the fan blower 19.

<Comparison of Operation Loops of SSF Evaporative Chiller with Current Chillers> Current operating commercial chillers are categorized into wet and dry chillers 61, 81 according to condenser 73 cooling method. The schematic pictures of operation loops of the wet and dry chillers 61, 81 are shown in FIGS. 8B and 8C, respectively. Their fabrication components are same except for components cooling condenser 73. Their same components are water tank heat exchanger 67, heat generator cooling water circulation pump 66, compressor 75, and condenser 73. The condenser 73 of wet chiller 61 is cooled with water cooled through cooling tower 79 and the dry chiller 81 uses air cooling fan 82 to cool condenser 73 which is combined with the air cooling fan 82 in one unit as shown in FIG. 8C. Among the components comprised of in the wet and dry chiller 61, 81, other components except water tank heat exchanger 67 and water circulation pump 66 cooling heat generator are supporting components to the compressor.

From the FIGS. 8B and 8C, it is understood that the wet chiller 61 consists of three loops of coolant circulation, 62, 70, 76 and that the dry chiller 81 comprises of two loops, 62, 70. Both primary coolant loops 65→64→63→67→65→66→65 cool the heat generator 64 of industrial facilities by circulation of water as an agent of coolant flowing through the primary coolant loop 62, which is marked in dot circles 80 as shown in FIGS. 8B and 8C. The hot water of both primary coolants flowing through in the primary coolant loops 62 is cooled by passing through the water tank heat exchangers 67 which are cooled by secondary coolants, chemical agents, passing through secondary coolant loops 70 in the water tank heat exchangers 67. The circulations of both secondary coolants are accomplished by operation of the compressors 75. Both hot chemical agents of secondary coolant are cooled and condensed by passing through condensers 73. The condenser of the wet chiller 61 is cooled with water supplied through the tertiary coolant loop 76 of cooling tower 79, but that of the dry chiller 81 is cooled by condenser 73 which is built in an air cooling condenser 83. Likewise, the current chiller is operated using more than two loops 62, 70 of coolant. On the contrary, the evaporative chiller 1 of the present invention is operated with one loop, as shown in FIG. 8A, which is similar to the primary loop 62 of the operation loops, shown in FIGS. 8B and 8C, of the current chillers 61, 81. Namely, the hot water generated by the heat generator 64 of industrial facility is cooled by passing through the SSF evaporative chiller 1 and then returned to the heat generator 64. Comparing the operation loops of the SSF evaporative chiller and current chillers shown in FIGS. 8A, 8B, and 8C, it is easy to be understood that the SSF evaporative chiller 1 of the present invention cools the heat generator 64 using only one simple coolant loop, which is corresponding to primary loop 62 of the current chillers 61, 81 marked in the dot circle 80 shown in FIGS. 8B and 8C and includes only one component, SSF evaporative chiller 1 with water circulation pump built in it. Hence, the cooling feature of the present invention is ability to cool heat generator without usage of the secondary and tertiary coolant loops 70, 76 which are indispensible in the current chillers 61, 81 and requires high construction cost, high electric consumption, and high maintenance expenses. Therefore, the SSF evaporative chiller 1 of the present invention can save a large amount of construction cost, electric consumption, and maintenance expenses, compared with those of the current chillers 61, 81. These are advantages of the present invention. The construction cost and electric consumption saving of the SSF evaporative chiller 1 are less than half cost of current chiller 61, 81 and in the range of 30 to 70%, respectively. For heat generators required to be cooled lower than room or environmental temperature, the present invention is not applicable to cooling of such heat generators, because its coolant water is cooled by ambient air of room or environmental temperature. The advantages and drawbacks of the SSF evaporative chiller of the present invention and current chillers are tabulated and compared in Table 1.

TABLE 1 Comparisons of Advantages between Current Chiller and SSF Evaporative Chiller Current SSF Item Commercial Chiller Evaporative Chiller Cooling Effect Water can be cooled lower Not cooled down lower than room or atmospheric temperature. temperature. Save operation expenses in case of cooling water down to only room or atmospheric temperature. White Smoke Yes, for wet chiller, since No, vapor is condensed in the Problem evaporated vapor is not chiller. condensed and discharged into environment. Ice Spike of Water Yes, for wet chiller. No. chiller is installed in building. Pipe in Winter Cooling Method Use compressor. Use evaporation and convection mechanism of water. Environment Effect Use cooling agent. No cooling agent. Environmentally friendly. Electric High consumption due to Low consumption due to usage of Consumption usage of compressor. pump and fan, 30-70% save. Manufacturing Less than half cost of current Cost chiller.

While the present invention has been described as having an exemplary design, this invention may be further modified within the concept and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention relates. 

What is claimed is:
 1. An evaporative chiller using string-screen-fill pack, comprising: a multiplicity of string-screen-fills each having a pair of vertical-string-screens on both sides of said string-screen-fill, each of said vertical-string-screen having vertical strings separated sufficiently apart from each other, wherein said vertical strings passing through and over semi-circular holes on the frame of said string-screen-fill; several of attachment tabs on said string-screen-fill frame, each of said attachment tabs locating on said string-screen-fill frame for joining said string-screen-fills, whereby said attachment tabs are joined by aligning said attachment tabs with and inserting into the counterpart tabs of said string-screen-fill to be joined by pressing.
 2. A string-screen-fill pack for use in evaporative chiller as recited in claim 1, wherein said string-screen-fill packs are employed in rectangular, square, pentagon, and hexagon cooling towers, wherein said rectangular cooling tower has two fill zones of said string-screen-fill packs near to two entrances of cooling air, wherein said square cooling tower may have said string-screen-fill packs to be placed near to two side or four side wall entrance of cooling air, and wherein said string-screen-fill packs are placed near to the entrances of cooling air at the entire outside walls of said pentagon and hexagon evaporative chillers.
 3. A string-screen-fill pack for use in evaporative chillers as recited in claim 1, wherein said string-screen-fill packs are employed in counter current evaporative chiller, and wherein said slanted string-screen-fill packs are installed in shape of V-type or X-type fill media. 